#include        <stdio.h>
#include        <stdlib.h>
#include        <termios.h>

#define  oops(s,x) { perror(s); exit(x); }

int main(int argc, char *argv[])
{
struct termios info;

if ( argc == 1 ) 
exit(0);

if ( tcgetattr(0,&info) == -1 )
oops("tcgettattr", 1);

if ( argv[1][0] == 'y' )
info.c_lflag |= ECHO ;/*打开提示符*/
else
info.c_lflag &= ~ECHO ;/*隐藏提示符*/

if ( tcsetattr(0,TCSANOW,&info) == -1 )
oops("tcsetattr",2);
	           
return 0;
}

